Failure to mount /sys in nested ‘guix shell ’ container
(address . bug-guix@gnu.org)
87v8jud4e7.fsf@inria.fr
Hi!
As reported by Konrad¹, nested ‘guix shell -C’ fails:
Toggle snippet (7 lines)
$ guix shell -CN guix \
--expose=/var/guix/daemon-socket/socket \
--expose=/gnu/store \
-- guix shell -C coreutils -- ls /
guix shell: error: mount: mount "none" on "/tmp/guix-directory.xO3FIx/sys": Operation not permitted
Strace shows this:
Toggle snippet (13 lines)
17541 clone(child_stack=NULL, flags=CLONE_NEWNS|CLONE_NEWCGROUP|CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWUSER|CLONE_NEWPID|CLONE_NEWNET|SIGCHLD) = 7
[…]
17551 mount("none", "/tmp/guix-directory.d6rKy1", "tmpfs", 0, NULL) = 0
17551 mkdir("/tmp", 0777) = -1 EEXIST (File exists)
17551 mkdir("/tmp/guix-directory.d6rKy1", 0777) = -1 EEXIST (File exists)
17551 mkdir("/tmp/guix-directory.d6rKy1/proc", 0777) = 0
17551 mount("none", "/tmp/guix-directory.d6rKy1/proc", "proc", MS_NOSUID|MS_NODEV|MS_NOEXEC, NULL) = 0
17551 mkdir("/tmp", 0777) = -1 EEXIST (File exists)
17551 mkdir("/tmp/guix-directory.d6rKy1", 0777) = -1 EEXIST (File exists)
17551 mkdir("/tmp/guix-directory.d6rKy1/sys", 0777) = 0
17551 mount("none", "/tmp/guix-directory.d6rKy1/sys", "sysfs", MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC, NULL) = -1 EPERM (Operation not permitted)
It does work if the nested ‘guix shell’ uses ‘-CN’ instead of ‘-C’,
thanks to this bit in (gnu build linux-container)
(mount-file-systems root mounts
#:mount-/proc? (memq 'pid namespaces)
#:mount-/sys? (memq 'net
namespaces)) ;<---
The reason for this bug seems to be given here:
It’s not clear whether there’s anything we can do, other than
recommending ‘-CN’ as well in the nested container.
Thoughts?
Ludo’.